Drive for deep-well pumping unit

ABSTRACT

The invention relates to the oil producing industry and, in particular, to a sucker-rod pumping unit for fluid withdrawal from a well, and may be used in other industrial and agricultural sectors. The objective of the invention is to simplify a design of a differential drive and to reduce costs at minimum pumping speeds of a pump jack. A drive for a deep-well sucker-rod pumping unit is disclosed. The drive comprises an electric motor coupled through a central gearbox to differentials comprising pinions and crown wheels, each differential having an output shaft coupled to a walking beam through a crank and a pitman arm. The invention is characterized in that the crown wheels of the differentials are fixed.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present patent application claims priority to Russian patent application RU 2019124896 filed Aug. 5, 2019, currently issued as a patent.

FIELD OF INVENTION

The invention relates to the oil producing industry and, in particular, to a sucker-rod pumping unit for fluid withdrawal from a well, and may be used in other industrial and agricultural sectors.

BACKGROUND

RU 2278994 (25 Oct. 2004) discloses a drive for a deep-well sucker-rod pumping unit. The drive comprises a motor, a gearbox, an assembly consisting of two pitman arms, at least one pinion and two central wheels. The at least one pinion and one of the central wheels or the two central wheels are coupled to the pitman arms, and the pitman arms having other ends coupled either through a walking beam to the deep-well sucker-rod pumping unit or directly to sucker-rods. This drive is insufficiently reliable and long-lived.

RU 2463479 (28 Dec. 2009) discloses a drive for a deep-well sucker-rod pumping unit. The drive comprises a motor coupled directly or through a gearbox to a differential comprising at least one pinion and two wheels. The drive comprises at least one further differential. Each differential has an output shaft and a housing fixedly coupled to a crownwheel. The output shaft and the housing of each differential are coupled to cranks and pitman arms. The main drawback of such a drive is its structural complexity at minimum pumping speeds of a pump jack.

The invention is intended for solving the problem of how to provide a simplified design of a differential and to reduce costs at minimum pumping speeds of a pump jack.

SUMMARY

The problem above is solved by that a drive for a deep-well sucker-rod pumping unit comprises an electric motor coupled through a central gearbox to differentials comprising pinions and crown wheels, each differential having an output shaft coupled to a walking beam through a crank and a pitman arm, and the crown wheels of the differentials being fixed.

The technical result provided by the above-indicated set of features is a simplification of the design of the differential and a reduction in the costs provided at minimum pumping speeds of the pump jack.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows a drive for a deep-well sucker-rod pumping unit, i.e. an external view of a pump jack (left-side view).

FIG. 2 schematically shows a cutaway view of a central gearbox assembled with differentials (cutaway view B in FIG. 3).

FIG. 3 schematically shows the drive for the deep-well sucker-rod pumping unit, i.e. view A in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A drive for a deep-well sucker-rod pumping unit comprises a Samson post 1, a walking beam 2, sucker-rods 3, an electric motor 4 coupled to a central gearbox 5 through a belt gear 6. An output shaft 7 of the central gearbox 5 engages pinions 8 of differentials 9. Output shafts 10 of the differentials 9, which are present on either side of the central gearbox 5, have cranks 11 installed thereon. The cranks 11 are coupled to pitman arms 12 that are coupled to an equalizer 13. Crownwheels 14 of the differentials 9 are fixed and rigidly attached to housing parts 15 of the differentials 9, while the housing parts 15 are rigidly attached to fixed supports 16 installed on a drive frame 17.

The drive for the deep-well sucker-rod pumping unit operates as follows.

The electric motor 4 rotates, through the belt gear 6 and the output shaft 7 of the central gearbox 5, the output shafts 10 via the pinions 8. The output shafts 10 cause, through the cranks 11 and the pitman arms 12, the walking beam 2 to perform reciprocating motions up and down. At minimum pumping speeds of a pump jack, a difference between angular velocities of the walking beam 2 at upstrokes and downstrokes is of no practical importance. This allows the design of the differential drive to be simplified extremely, as well as the costs for it to be reduced extremely.

The present drive for the deep-well sucker-rod pumping unit may be fabricated by using standard equipment, familiar materials and familiar techniques. 

What is claimed is:
 1. A drive for a deep-well sucker-rod pumping unit, comprising an electric motor coupled through a central gearbox to differentials comprising pinions and crown wheels, each differential having an output shaft coupled to a walking beam through a crank and a pitman arm, and the crown wheels of the differentials being fixed. 